SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbdaf9ebdec886802aa374999332fafe7e4855632352f6d550344de140726978' 
  AND token = 'KZ34KdMytTWddKurUTUpmYSDDkVldGGkI3xqWKN6M7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}